Slump meter



March 1, 1966 L. G. HILKEMEIER SLUMP METER Filed Dec. 5, 1963 FIG. I FIG. 2

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\ x LOUIS G. HILKEMEIER INVENTOR.

United States Patent 3,237,437 SLUMP METER Louis G. Hilkemeier, Holyoke, Mass, assignor to Worthington Corporation, Harrison, N.J., a corporation of Delaware Filed Dec. 3, 1963, Ser. No. 327,787 2 Claims. (CI. 73-53) This invention relates to concrete mixing equipment. More particularly the invention relates to a slump meter for indicating the consistency of materials being mixed in the mixing drum.

As is well known in the art of concrete mixing, careful control must be maintained over the consistency or slump of the mix. Heretofore this control has been maintained in various ways, such as trial and error; gauges associated with the prime mover; electric probes extending into the mixed concrete; and rotating paddles in the mixed concrete to record the shearing force thereof. Each of these methods of control has met with only limited success.

An object of the present invention is to provide an improved slump meter which insures the quality of the concrete; "which will eliminate the complexity of procedure and equipment formerly required to determine when the concrete batch was mixed to the desired slump; which will eliminate excess and unwarranted usage of the mixing equipment due to incorrect slump indication; which is of simple design, reliable and accurate; which is readily applicable to use on existing mixing equipment with a minimum degree of modification; which operates on the principle that the torque of the mixing drum varies as the consistency of the mix; which provides visual indicating means to determine the degree of slump; which utilizes yieldable means to absorb the torque exerted by the mixing apparatus; which utilizes the variations in torque to actuate the visual indicating means so that the slump of the mixture in the mixing drum can be observed.

Other objects and advantages will be apparent from the following description of one-embodiment of the invention and the novel features will be particularly pointed out hereinafter in the claims.

In the drawings:

FIGURE 1 is a front elevation of a mixing apparatus in which the improved slump meter is embodied.

FIGURE 2 is a side elevation of the mixing apparatus in which the improved slump meter is embodied.

FIGURE 3 is an enlarged partial sectional view of the improved slump meter, as shown in FIGURE 1.

In the embodiment of the invention illustrated in the drawings, the novel slump meter is shown in association with mixing apparatus designated generally 10, which apparatus is well known in the art.

Mixing apparatus as shown in FIGURES l and 2 may be of any typical design that includes the usual standard components. Frame has a base 22 from which extends parallel spaced columns 24 which are joined at the upper end by beam 26. Intermediate space 22 and beam 26 is a cross-mounting member 28 which is fixedly connected to column 24 in any suitable manner, as by welding. A shaft 30 is suitably journaled by member 28 and extends therefrom to be fixedly connected driven sprocket 32 of the mixing drum 34. Shaft 30 will suitably support the rotatable motion of mixing drum 34 and if desired additional support may be used.

The rotatable power is supplied by an engine and transmission unit 40 which is suitably mounted on base 22 of frame 20. Engine and transmission unit 40 has an output shaft 42 capable of being driven in either direction. Shaft 42 is connected to drive shaft 44 as at coupling 46. The end of drive shaft 44 remote from coupling 46 has a worm gear 48 mounted thereon and is suitably disposed iCe in gear 'box 50. Gear box 50 is mounted on shaft 60 as by suitable bearing means 62. Shaft 60 is rotatably mounted in housing 64 by bearing 66. Housing 64 is fixedly connected to extension arm 63 of frame 20. Shaft 60 has a driven gear 70 mounted thereon within the gear box 50 and in engagement with worm gear 48. A drive sprocket 72 is mounted on the end of shaft 60 furthest from gear 70. A chain 74 connects drive sprocket 72 to drive sprocket 32 and will transmit the rotatable power from one to the other respectively as described hereinafter.

On operation of engine and transmission unit 40 rotatable power Will be transmitted through output shaft 42 and drive shaft 40 to worm gear 48 which will drive gear 70 and drive sprocket 72 of driven shaft 60. Drive sprocket 72 will in turn actuate chain 74 and driven sprocket 32 so that the mixing drum 34 will be caused to rotate in either the clockwise or counterclockwise direction. For convenience the clockwise direction is indicated by arrow 76 as the mixing direction of the concrete and the counterclockwise direction is indicated by arrow 78 as the direction of rotation for discharge of the concrete.

The rotation of mixing drum 34 will develop a clockwise directed torque which is proportional to the load therein and as the slump of the mixture increases in mixing drum 34 the torque will also increase. Since the gear box 50 is mounted on shaft 60 it is subject to this torque and therefore means must be provided to prevent the gear box 50 from rotating around shaft 60. Such means are provided 'by yieldable assembly 80.

Yieldable assembly 80 as illustrated in FIGURE 3 in cludes a cylinder 82 and a piston 84 fixedly connected to a rod 86. The end of cylinder 82 remote from rod 86 has a bracket 88 fixedly connected thereto. Bracket 88 is pivotally connected to yoke 90 as at 92. The end of rod 86 remote from piston 84 has a yoke 94 connected thereto which is pivotally connected as .at 96 to bracket 98 of gear box 50. Cylinder 82 has a chamber 100 formed therein which is divided by piston 84 into a gauge portion 102 and a bypass portion 104. Chamber 100 is filled with a non-compressible fluid and rendered leakproof. A line is connected to cylinder 82 and is in communication with gauge portion 102. A visual indicating means or gauge .120 is connected to line 110 at the end thereof remote from cylinder 82. Gauge has an indicator 122 and a suitably calibrate-d scale 124. A fluid gauge damper 126 is disposed in line 110 intermediate gauge 120 and cylinder 82 to permit accurate and steady readings of gauge 120. A bypass line 130 is connected to cylinder 82 and is in communication with bypass portion 104. The bypass line 130 connects into line 110 intermediate gauge damper 126 and the connection with cylinder 82. A check valve 132 is disposed in bypass line 130 so as to prevent fluid in line 110 from entering bypass portion 104 while permitting fluid in bypass line 130 to enter line 110 and gauge portion 102. In addition to chamber 100 being filled with non-compressible fluid, lines 110 and 130 are also substantially filled with said fluid.

Keeping in mind that an increase in slump or consistency of the mixture in mixing drum 34 will cause an increased torque to be applied against gear box 50, the operation of the slump meter of the present invention will now be described. The torque acting on gear box 50 will be balanced by and in turn transmit a linear force to rod 86 and piston 84 causing the pressure of the fluid in gauge portion 102 and line 110 to increase; which increase will be indicated by gauge 120. Scale 124 will be suitably marked so as to convert the increase in pressure to the proportionate increase in slump and in this way indicate when the desired slump of the mixture in mixing drum 34 has been reached. As the slump increases, the

piston will move through a distance X. To prevent excessive buildup of the pressure in gauge portion 102 a predetermined amount of fluid will leak past the piston 84 into bypass portion 104. Check valve 132 will pre-. vent fluid in line 110 from being diverted into the bypass portion 104. The distance X represents the typical movement of piston 84 and is represented by the dotted lines thereof. This movement is correlated with the indicated dotted movement of indicator 122 "and will represent the reading corresponding to the slump of the mixture in mixing drum 34. On gauge 120 signalling that the desired slump has been reached the operator will cease the mixing operation.

Readings of gauge 120 will only be taken during the mixing operation and when the mixture in mixing drum 34 is being discharged the torque will be exerted in the opposite direction, thus urging gear box 50 and piston 84 and rod 86 also in the opposite direction. This will act to compensate for any leakage which occurred when the torque was applied to cylinder 82 during the mixing operation by having the fluid in the bypass portion 104 returned to the gauge portion 102 through bypass line 130, check valve 132 and line 110. Thus cylinder 82 is returned to its initial condition. Of course to prevent any slight mis-settings of gauge 120 a zero setting means for gauge 120 may be provided so that prior to the mixing operation gauge 120 would be set at zero from which point the slump would be indicated as described hereinbefore.

It will be understood that various changes in the details, materials and arrangements of parts which have been herein described and illustrated in order to explain the nature of the invention may be made by those skilled in the art within the principles and scope of the invention as expressed in the claims.

What is claimed is:

1. A slump meter for visually determining the consistency of the mixture in a mixing drum of mixing apparatus comprising:

(a) a frame on which the mixing apparatus is rotatably mounted;

('b) a shaft rotatably mounted on the frame in spaced relation to the mixing drum;

(-c) power transmission means connecting the mixing drum to one end of the shaft whereby on rotation of the shaft the mixing drum will be rotated;

(d) a gear box means mounted on the other end of the shaft;

(e) a source of rotatable power connected to the gear box means;

(if) the gear box means containing worm gearing to transmit the rotatable power from the source thereof to the shaft;

(g) means pivotally connected at one end to the gear box means and at the other end to the frame, to yieldably restrain the gear box means from turning responsive to the torque developed by the shaft and 5 mixing drum; said pivotally connected means comprising a sealed hydraulic cylinder, a chamber means formed within the cylinder having substantially noncompressible fluid therein, a piston and rod disposed within said chamber means, said piston dividing said chamber means into a gage portion and a bypass portion, said rod connected at one end to said piston and at the other end forming the pivotal connection with the gear box means to drive the piston during mixing thereby transmitting the mixing torque to the fluid in the chamber means, and to retract the piston during discharge of the mixing apparatus;

(h) visual indicating means comprising a line connected to the gage portion of the chamber means in said cylinder and a gage connected to the line to indicate the pressure of the fluid in the gage portion;

(i) and a bypass means comprising a bypass line connected between the bypass portion of the chamber means in the cylinder and the line of the visual indicating means, and a check valve in the bypass line to prevent the fluid in the line of the visual indicating means from entering the bypass portion of the chamber means and to permit the fluid from the bypass portion of the chamber means to enter the line of the visual indicating means in response to the movement of the piston in the chamber means during mixing and discharge respectively, of the mixing apparatus.

2. An apparatus as in claim 1 wherein said piston is slideably fitted in said chamber means to permit a pre- 35 determined amount of fluid to leak past said piston from said gage portion to said bypass portion in response to movement of the piston in the chamber means during mixing. References Cited by the Examiner UNITED STATES PATENTS 1,520,842 1/ 1924 Newman 92-86 X 1,822,628 9/1931 Lincoln 73141 X 1,980,184 11/1934 Butcher 73-54 X 2,019,755 11/1935 Zerbe et al 73136 2,282,652 5/1942 Henning 921l8 X 2,643,542 6/1953 Cronk 7354 RICHARD C. QUEISSER, Primary Examiner.

DAVID SCHONBERG, I. W. MYRACLE,

Assistant Examiners. 

1. A SLUMP METER FOR VISUALLY DETERMINING THE CONSISTENCY OF THE MIXTURE IN A MIXING DRUM OF MIXING APPARATUS COMPRISING: (A) A FRAME ON WHICH THE MIXING APPARATUS IS ROTATABLY MOUNTED; (B) A SHAFT ROTATABLY MOUNTED ON THE FRAME IN SPACED RELATION TO THE MIXING DRUM; (C) POWER TRANSMISSION MEANS CONNECTING THE MIXING DRUM TO ONE END OF SHAFT WHEREBY ON ROTATION OF THE SHAFT THE MIXING DRUM WILL BE ROTATED; (D) A GEAR BOX MEANS MOUNTED ON THE OTHER END OF THE SHAFT; (E) A SOURCE OF ROTATABLE POWER CONNECTED TO THE GEAR BOX MEANS; 